Nanocomposites based on plasticized starch and rectorite clay: structure and properties

Sodium rectorite clay (REC) was attached to cationic guar gum (CGG) using a cationic-exchange reaction to obtain CGG modified-REC (CREC). It was found that CGG appeared on the surface of REC's layered structure and represented about 30.1% wt. in CREC. REC and CREC were, respectively, used as fillers in a plasticized starch (PS) matrix to prepare PS/REC and PS/CREC composites using the casting process. Rapid Visco Analyser and scanning electron microscopy revealed that an interaction existed between the REC (or CREC) filler and the matrix. Both REC and CREC had obvious reinforcing effects on the matrix. Compared to the neat matrix, REC or CREC improved the thermal stability of the composites. By increasing the filler content from 0 to 10 wt%, water vapor permeability (WVP) values of PS/REC composites obviously decreased, while WVP values of PS/CREC composites decreased slightly.